Answer:
z = 12xy
Step-by-step explanation:
Given z varies jointly with x and y then the equation relating them is
z = kxy ← k is the constant of variation
To find k use the condition when x = 2 and y = 3, z = 72, that is
72 = k × 2 × 3 = 6k ( divide both sides by 6 )
12 = k , then
z = 12xy ← equation of variation
